Longitudinal Assessment of Bariatric Surgery (LABS) consortium was established in 2003 and was conceived to address important issues in bariatric surgery and metabolism in the obese and morbidly obese. LABS explores relationships of patient characteristics, clinical conditions, serologic and genetic markers, and clinical, psychosocial and health economic outcomes. The primary achievements of LABS have been to establish a research consortium and its infrastructure; define the domains of exploration, specific research questions and an effective study design to efficiently address those questions; identify appropriate metrics; design and implement a web-based data collection system and an extensive database; complete a cohort of over 5000 participants to study the short-term safety of bariatric surgery; enroll over 2000 people into a person cohort intended to be the focus of longer-term follow-up to address safety and efficacy of bariatric surgery; and implement 2 sub studies focusing on the mechanisms of diabetes resolution and more in-depth psychiatric and quality of life data, respectively, than in the full cohort. During this proposed continuation of LABS we will build on the rigorous research infrastructure across 9 clinical sites at the 6 Clinical Centers LABS investigators will address scientifically important Research protocols were developed and instituted to include a 30 day outcomes (safety, LABS-1) study of approximately 5,000 participants and a smaller cohort of 2,400 participants to conduct a detailed study of the longitudinal effects of bariatric surgery. LABS-3 diabetes is a sub-study of mechanisms of weight loss and impact on type 2 diabetes in gastric bypass patients. This proposal is the OHSU response to the limited competition RFA issued by the NIDDK soliciting cooperative agreement applications from investigators currently participating in the LABS consortium to study bariatric surgery and its role in the understanding of obesity and its complications for an additional five years. An extension to LABS will evaluate emerging effects of surgery and effects that change overtime. RELEVANCE (See instructions): More than 5% of adults in the US meet the weight criteria for bariatric surgery but less that 2% of the eligible patients undergo this therapy per year. Research to define the benefits and risks is necessary to inform the question regarding the extent to which bariatric surgery should be done in eligible patients.